関係詞と先行詞

\documentclass[b5j,10pt,twoside]{tetsujsarticle}
\usepackage{tetsuryoku}

\def\先行詞#1{%
  \tikz[remember picture,baseline=(A.base)]%
    \node[inner sep=0pt, outer sep=0pt, black,thick] (A) {\下線{\vphantom{hp}#1}};%
}
\newcommand*\関係詞[2][0pt]{%
  \tikz[remember picture,baseline=(B.base)]%
    \node[inner sep=0pt, outer sep=0pt, black,thick] (B) {\下線{\vphantom{hp}#2}};%
  \tikz[overlay,remember picture,black,thick,>=stealth]{%
    \draw[black,thick,->] (B) -- ++(0,-1.2em) -| ($(A.south) + (#1,0pt)$)%
        node[below, near start] {};%
  }%
}

\begin{document}

Can you see a \先行詞{boy} \関係詞{who} is running along the river?

\br1

It can help him accept the fact that there is \先行詞{much} in the world that differs greatly from what he sees around him and to \関係詞{which} he must learn to adapt himself.

\br1

It can help him accept the fact that there is \先行詞{much} in the world \関係詞[3pt]{that} differs greatly from what he sees around him and to \関係詞[-3pt]{which} he must learn to adapt himself.


\end{document}